body {
    margin: 0;
    display: flex;
    height: 100vh;
}

.sidebar {
    width: 250px;
    background: url('./back/login-bg.jpg') no-repeat center center/cover;
    color: #ecf0f1;
    padding: 15px;
    box-shadow: 2px 0 5px rgba(0, 0, 0, 0.1);
    display: flex;
    flex-direction: column;
    height: 100%;
}

.sidebar h2 {
    text-align: center;
    margin-bottom: 20px;
}

.sidebar ul {
    list-style: none;
    padding: 0;
    flex-grow: 1;
}

.sidebar ul li {
    margin: 10px 0;
}

.sidebar ul li a {
    color: #ecf0f1;
    text-decoration: none;
    display: block;
    padding: 10px;
    border-radius: 4px;
    transition: background 0.3s;
}

.sidebar ul li a:hover {
    background-color: rgba(0, 0, 0, 0.2);
}

.content {
    flex-grow: 1;
    background-color: #ecf0f1;
    padding: 20px;
    overflow-y: auto;
}

.content-section {
    margin-bottom: 20px;
}

.hidden {
    display: none;
}

.course-container {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
    gap: 20px;
    margin-top: 20px;
}

.course-card {
    background: white;
    padding: 15px;
    border-radius: 8px;
    box-shadow: 0 2px 5px rgba(0, 0, 0, 0.1);
    transition: transform 0.3s;
}

.course-card:hover {
    transform: scale(1.05);
}

.course-card h2 {
    font-size: 18px;
    margin: 10px 0;
}

.course-card p {
    margin: 5px 0;
}

.course-card .btn {
    margin-top: 10px;
    display: inline-block;
    background-color: #3498db;
    color: white;
    padding: 10px 15px;
    text-decoration: none;
    border-radius: 4px;
    text-align: center;
    transition: background 0.3s;
}

.course-card .btn:hover {
    background-color: #2980b9;
}

.info-form {
    background: white;
    padding: 20px;
    border-radius: 10px;
    box-shadow: 0 2px 5px rgba(0, 0, 0, 0.1);
    max-width: 500px;
    margin: 0 auto;
}

.info-form h2 {
    text-align: center;
    margin-bottom: 20px;
}

.info-form label {
    display: block;
    margin: 10px 0 5px;
    font-weight: bold;
}

.info-form .input-field {
    width: 100%;
    padding: 10px;
    margin-bottom: 15px;
    border: 1px solid #ccc;
    border-radius: 5px;
}

.info-form .btn {
    width: 100%;
    background-color: #3498db;
    color: white;
    padding: 10px;
    border: none;
    border-radius: 5px;
    cursor: pointer;
    font-size: 16px;
}

.info-form .btn:hover {
    background-color: #2980b9;
}

.enrollment-list {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
    gap: 20px;
    padding: 0;
    list-style: none;
}

.enrollment-item {
    background: white;
    padding: 15px;
    border-radius: 8px;
    box-shadow: 0 2px 5px rgba(0, 0, 0, 0.1);
}

.enrollment-item h2 {
    margin: 10px 0;
    font-size: 18px;
}

.enrollment-item p {
    margin: 5px 0;
}

.enrollment-item .btn {
    margin-top: 10px;
    display: inline-block;
    background-color: #e74c3c;
    color: white;
    padding: 10px 15px;
    text-decoration: none;
    border-radius: 4px;
    text-align: center;
    transition: background 0.3s;
}

.enrollment-item .btn:hover {
    background-color: #c0392b;
}

.enrollment-item .status {
    font-weight: bold;
    font-size: 14px;
    margin-top: 10px;
    padding: 5px 10px;
    border-radius: 4px;
    display: inline-block;
    color: white;
}

.enrollment-item .status.ongoing {
    background-color: #27ae60; /* 进行中 - 绿色 */
}

.enrollment-item .status.completed {
    background-color: #2980b9; /* 已完成 - 蓝色 */
}

.enrollment-item .status.cancelled {
    background-color: #e74c3c; /* 已取消 - 红色 */
}

